goal statement: objectives: required materials: … · 2017-11-29 · farmers who grow field crops...

The Science of Maryland Agriculture

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry,

national origin, marital status, genetic information, political affiliation, or gender identity or expression.

GOAL STATEMENT:Students will explain the role of soybeans and other legumes in making nitrogen available in a form that

can be used by plants, animals, and humans. They will also identify a wide variety of products that contain soybeans.

OBJECTIVES:• Students will identify the main parts of a soybean plant.• Students will interpret the nitrogen cycle as it relates to animals, plants, and humans. • Students will identify products that contain soybeans.• Students will research soybeans to determine how they are grown, harvested, and used and why

they are important in the food chain.

REQUIRED MATERIALS: • Soybean plant including the root system or photo of soybean plant• Magnifying glass or microscope for viewing root nodules• Dried soybeans for observation • Photos of Maryland grain crops• Copies of soybean plant diagram (1 per student)• Copies of nitrogen cycle fill-in diagram• Set of items or photos of items for soybean product activity (1 per group, or subsitute for actual

items)

AMOUNT OF TIME TO ALLOW: 60 minutes. Extension activities will take additional time.

Edition 3 (2016)

Soybeans are the number two Maryland-grown crop in terms of total bushels harvested per year. Soybeans are used in various ways. As whole seeds, soybeans are planted to produce more soybeans

for the next growing season. They are also roasted as snacks and eaten as edamame (green, non-dried soybeans). Soybeans are also processed in different ways. The oil can be extracted from the beans and used

as a component in animal and human foods. Soybeans can be ground into meal, which is typically made into animal feed. The hulls, or dried pods, are used in animal feed and in water purification research. By weight,

soybeans yield, on average, 18% oil, 79% meal, and 3% waste (which is typically used as a byproduct).

In terms of taxonomy, soybeans plants are classified as legumes. Legumes are plants that provide a home for special nitrogen-fixing bacteria in their root systems. Legumes and the bacteria housed in their roots share a symbiotic relationship, or a relationship from which they both benefit. The bacteria obtain nutrients from the

plant and, in turn, provide nitrogen to the plant. These bacteria remove nitrogen from the air and convert it to a form of nitrogen that soybeans use to make protein, an important nutrient required for the plants to grow. For this reason, soybeans are one of the world’s most inexpensive sources of dietary protein.

Most other field crops that farmers grow – aside from soybeans – are classified as grains. Grain crops, unlike legumes, belong to the grass family. Corn, wheat, and barley are examples of grain crops. (Although soybeans are not scientifically classified as grains, they are often considered by agricultural producers to be grains for simplicity.) Grains are a major food source for people and animals, and they require a large amount of nitrogen in the soil for proper growth.

Farmers who grow field crops (such as corn, hay, soybeans, and wheat) use the nitrogen-fixing property of legumes to their advantage. To ensure that soil nitrogen is continually replenished, farmers rotate crops. For example, soybeans are typically planted following the harvest of a crop such as wheat. The following year, corn will be planted in that same field that grew soybeans the previous year. Therefore, using a legume such as soybeans in a crop rotation ensures that soil will continually have sufficient plant-available nitrogen for plants to grow.



10 minutes

Show students photographs of farm crops grown in Maryland. (The photos are labeled with the crop name; cover or remove the label before showing the photos to students.) One at a time, show the photograph and ask students to identify the crop shown in each. Write the name of each crop on the board. Once all photographs have been examined, write the word “grain crops” above the list. Discuss what grain crops are and how they are used by people and animals.

Next show the class a photo or sample of a complete soybean plant that includes the root system. Ask the students to identify what kind of grain the plant grows. (If a soybean plant is not available, show students the soybean plant diagram.) Once identified, write the word “soybean” on the board in a separate group from where the grain crops are listed. If soybeans were listed as a grain crop, erase the word from that group. Then write the following words on the board beside the word soybeans: peas, alfalfa, lentils, beans, peanuts, and soybeans. Finally, write the word “legume” above this list. Ask students if they know what a legume is. How do the plants in the legume category differ from those in the grain category? Discuss ideas.

Activity 11. Give each student a copy of the soybean plant diagram. 2. Ask them to locate and label the following parts: pods, leaves, seeds, stem, nodules, flowers,

roots. They may discuss their ideas with a partner to ensure that their labeling is correct. 3. Review the parts of the plant and ask students if they know the function of each plant part. You

may choose to have students use colored pencils to make each part of the diagram a different color.

4. Ask students if they notice anything unique about this diagram or a part of the plant they haven’t seen on other plants. Help students understand that root nodules are a characteristic unique to legumes. Explain how these nodules are important to soil fertility and plant growth because of the nitrogen-fixing qualities of the bacteria that reside in the nodules.

5. Ask students why nitrogen is important for plants to grow. Discuss their ideas. Provide each student with a copy of “The Nitrogen Cycle” worksheet.

6. Help students understand that nitrogen is vital to all life. Without it there would be no plants, animals, or other organisms. Lead a discussion of the way nitrogen cycles from the air into the ground and back through the organism to the soil and atmosphere. Have the students place the 6 descriptions (see below) on the correct part of the diagram of the nitrogen cycle. Be sure to introduce these steps.

a. Nitrogen is present in the atmosphere.b. Bacteria in roots of legumes take nitrogen from air and supply it to the legume where it is

converted into protein and other nitrogen compounds.c. Nitrogen is released in the soil.d. Plants use soil nitrogen for their growth.e. Animals eat plants to take in nitrogen and meet their protein needs.f. Animals and plants produce waste products or die and decompose, adding nitrogen back

to soil.g. Denitrifying bacteria in the soil release nitrogen back into the air.

Activity 21. To test student understanding of nitrogen cycle processes, ask each student to draw an arrow on

a piece of paper. Explain that you will read several statements. After each statement, students are to hold up their papers with the arrow pointing upward for an answer of “increase”, downward for an answer of “decrease”, or sideways for an answer of “no change/little change” of nitrogen in the soil.

2. After students have made their selections for a statement, review the reasons given and discuss/clarify as needed. Instead of using arrows, another option for this activity would be to designate three areas of the classroom as increase, decrease, or no change/little change and have students move to the areas they choose.

a. A farmer plants soybeans in the same field three years in a row. (Increase. The nitrogen-fixing bacteria in the roots of soybeans add nitrogen to the soil. The amount of nitrogen will increase over time.)

b. A farmer plants only corn in the same field five years in a row. (Decrease. Corn removes nitrogen from the soil and it is not a legume, so it is unable to add



30 minutes



nitrogen to the soil.)

c. A homeowner spreads poultry manure over her garden before she plants vegetables. (Increase. Manure from poultry contains nitrogen and can be used as a natural fertilizer to supplement the nitrogen in the soil.)

d. After soybeans have been harvested in the fall, nothing is planted until the spring. (No change or little change. There are no plants growing and removing nitrogen. Note: Some nitrogen may be washed from the soil as a result of rainfall.)

e. A farmer practices crop rotation by alternating the crops planted each year. For example: soybeans (year 1), corn (year 2), soybeans (year 3), corn (year 4). (No change or little change. Crop rotatation tends to balance the amount of nitrogen in the soil.)

f. A farmer applies chemical fertilizers to the soil as soybeans are planted. (Increase. Chemical fertilizers are made by people and used to supplement nitrogen in the soil that was put there by bacteria in the roots of legumes.)

• chocolate candy • hot dogs• frozen dinners• diet food products• cooking oils• margarine• noodles• cereals• facial tissues• infant formula • soap • detergent • livestock feed • cosmetics

• cleaning materials • plastics • metal fork or spoon• bakery products• canned foods• paper plates• pancake mix• muffin mix• ink• cake mix• polyester fabric• pet food• shampoo• rubber

Activity 3 1. Pass some soybean seeds or photos of soybeans around the room. Inform the students

that soybeans are one of the world’s most inexpensive sources of protein for humans and animals. Protein is an important nutrient that humans and animals need for building body tissues like muscle and skin.

2. Place all of the photos of soybean products in a box. (You may substitute samples of actual products in place of the photo set.)

3. Ask each student to pull one item or photo out of the box without looking. Have each student predict whether their object contains soybeans. Only three on the list of products (see below) do not contain soybeans: tissues, paper plate, and metal fork or spoon. With the class, discuss how soybeans are a component of many food and non-food products we use every day.

The items/pictures include:

• paints (water based)• adhesives• particle board• crayons (soy crayons are

available from the Maryland Soybean Board)



Have students observe root nodules under a magnifying glass or microscope to examine their structure.

Research the major uses of soybeans and present the results to the class.

Search online for “Soybeans Go to School kit, Michigan”. This website offers several suggested lessons in detail that provide hands-on lessons for youth. We suggest the following. In the “Racey Soy” unit — “Examining the Bean,” page 23-24 or in the “Can the Golden Bean Be Green” unit — “Ink Is Ink Is Ink, Isn’t It?” page 45-46.

Search online for “A Bean is a Seed, Oklahoma”. This is another hands-on lesson designed for younger children but may be adaptable for middle school.

Talk to local farmers and ask them why they grow soybeans. Report to the class the reasons soybeans are a popular cash crop in your county and in the state. (This is a good public speaking opportunity, too.)

20 minutes

Review some of the basic facts about soybeans that are found in the Background Information section. Ask students to line up in the center of the room. Read the following statements one at

a time. For each statement, have students move to one side of the room if they think it is true and the other side if they think it is false. Ask students on each side of the room to give reasons for

their choices. If the statement is false, explain why.

1. Peas, alfalfa, lentils, beans, and soybeans are classified as a group of plants called legumes. (True)

2. Legumes have special bacteria in their roots that remove carbon from the air. (False—they remove nitrogen from the air.)

3. Although soybeans are technically not grains, they are often grown by grain farmers. (True)4. The bacteria in the roots of soybeans use nitrogen from the air to make carbohydrates. (False—

they make protein. Legumes are very high in protein because they are the only plants with nitrogen-fixing root bacteria.)

5. Soybeans are one of the world’s most expensive sources of protein. (False—soybeans are a relatively inexpensive source of protein.)

6. Maryland farmers grow more acres of soybeans than corn. (False—corn is the #1 crop and soybeans are the #2 crop.)



“Just the Beginning, Life of a Young Sprout.” 2010, Maryland Soybean Board, Laser Letters and Agri-Media Services, Easton, MD.

The Maryland Soybean Board website, <www.mdsoy.com>.

“Windows to the Universe: The Nitrogen Cycle” website, <www.windows2universe.org/earth/Life/nitrogen_cycle.html>.

Minnesota Ag in the Classroom website, <www.minnesota.agclassroom.org>.

Grow Next Gen website, <www.grownextgen.org>.

Student understanding can be evaluated through class discussion or assessment of completed activity data sheets. The following questions may also be used to evaluate student learning.

1. What is a legume? How is it different from a grain?2. How do soybeans increase soil fertility?3. Name five products that can be made from soybeans.

• Grain Farmer – A grain farmer plants, harvests, and sells soybeans and other grains.• Grain Marketer – A grain marketer buys soybeans from the farmer and resells them to the

poultry industry and other markets that utilize soybeans.• Food Scientist – A food scientist finds more uses for soybeans for various food products and

industrial uses• Agriculture Scientist – An agriculture scientist researches the properties of soyebans to assist in

the development of a etter more disease-resistant bean. • Plant Breeder – A breeder develops better soybeans with traits such as better nutritive content

and pest resistance.• Pathologist – A pathologist devises ways to protect soybeans from diseases.• Entomologist – An entomologist devises ways to protect soybeans from insects that are

detrimental to growth.• Agronomist – An agronomist devises best management practices for growing soybeans. • Grain Silo Operator – A grain silo operator measures the number of bushels and probes

soybeans to find the moisture and test weight of soybeans sold to the local granary. • Grain Hauler – A grain hauler drives the truck loads of soybeans to buyers. • Grain Processor – A grain processor uses soybeans in various ways such as extracting oil for

cooking and feed for chickens and making the oil into ink.

University of Maryland Extension programs are open to all and will not discriminate against anyone because of race, age, sex, color, sexual orientation, physical or mental disability, religion, ancestry, national origin, marital status, genetic information, political affiliation, or gender identity or expression.

Name:

Date: Period:

Parts of a Soybean Plant (Soybeans are Legumes!)

Label the parts of the plant listed below. Write a description of the function of each plant part.

flowers leaves seeds inside pods stem roots root nodules


“Diagram of soybean plant” by the International Institute of Tropical Agriculture is licensed under CC NC-2.0.


Name:

Date: Period:

The Nitrogen CycleNitrogen can exist in many different places and in many different forms. It can also change from one form to another. The processes by which nitrogen changes forms and the states it can exist in are collectively called the nitrogen cycle.

Soybeans (and other legumes) are an important part of the nitrogen cycle. The unique root nodules on a soybean plant provide a habitat for bacteria that fix, or convert, nitrogen in the atmopshere into soil nitrogen. In this way, soybeans help to increase soil nitrogen and thus soil fertility.

The nitrogen cycle is very complex; the chart on the following page provides a simplified diagram. The following eight items are parts of the cycle. Read the description for each, and then fill in each box on the diagram with the correct item. (Note: the red boxes on the diagram correspond to processes that change nitrogen, and the black boxes corerspond to states in which nitrogen can exist.)

STATES• Nitrogen in atmosphere – Most of the Earth’s nitrogen (about 78%) is in the atmopshere. This form of

nitrogen is not usable by most organisms.• Nitrogen in animal protein – When an animal eats a plant, its body converts the nitrogen in the plant

to proteins. Proteins are an essential part of many body functions, like building muscle and creating antibodies.

• Nitrogen in plants – In plants, nitrogen is a major component of chlorophyll, the molecules that absorb sunlight during photosynthesis. Nitrogen is also used by plants to build tissues and exchange energy.

• Nitrogen in animal waste – Excess nitrogen that isn’t needed by the animal is excreted in manure.• Nitrogen in soil – Nitrogen enters the soil from the atmosphere (via fixation by bacteria found in the root

nodules of legumes) and from plant and animal waste (via decomposition by soil microbes). Some nitrogen is available for plants to take up by their roots and use for growth. Other forms of nitrogen are not able to be used by plants until they are converted to available forms by soil microbes.

PROCESSES• Nitrogen volatalizes – Volatalization is when nitrogen in the soil spontaneously changes into atmopsheric

nitrogen. Through this process, soil nitrogen is lost and soil fertility decreases.• Bacteria and fungi break down nitrogen – Soil microbes (like bacteria and fungi) decompose nitrogen from

organic sources (like manure and plant material) and turn it into a form that plants can utilize. This process increases soil fertility.

• Bacteria in legume root nodules fix nitrogen – Bacteria in the root nodules of soybeans and other legumes fix, or convert, nitrogen in the atmosphere to a form of soil nitrogen that plants can utilize. This process increases soil fertility.



Name:

Date: Period:

The Nitrogen Cycle



Name:

Date: Period:

The Nitrogen Cycle – Teacher Key


Nitrogen in atmosphere

Nitrogen in plants

Bacteria in legume root nodules fix nitrogen

Bacteria and fungi break down nitrogen

Nitrogen volitalizes

Nitrogen in animal waste

Nitrogen in animal protein

Nitrogen in soil


Name:

Date: Period:

Soybean Fact Matching Activity

Plants need the following to grow: 80 % of the air we breathe.

Nitrogen makes up two or more year rotation.

Nitrogen is needed for to keep the soil rich and to produce the best plant growth.

Farmers grow nitrogen-producing crops in 120 days (3 months).

Grass crops include and harvested in the fall.

Grass crops depend on soil nitrogen sunlight, water, minerals, food, and air.

Soybeans normally grow to maturity corn, wheat, rice, and barley.

Soybeans are planted in the spring where farmers alternate crops to replace nitrogen in the soil.

Crop rotation is a farming practice provided by legumes or a chemical fertilizer containing nitrogen.

Farmers alternate crops on a soybeans to make protein.


goal statement: objectives: required materials: … · 2017-11-29 · farmers who grow field crops...

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